Modern businesses rely on being able to transfer document images from one location to another. With the adoption of Group 3 digital standards in 1980 by the Comité Consultatif International Téléphonique et Télégraphique (CCITT) (or the International Telegraph and Telephone Consultative Committee), facsimile (FAX) devices have become extremely prevalent in offices. Facsimile devices typically operate by scanning a document line by line to detect light and dark areas. These light and dark areas are then converted into binary digits. A representation of these light and dark areas is then transmitted across a telephone line to a receiving unit that in turn uses the received representation to generate dots on paper. The result is a reasonably good copy of the original document. Originally, facsimile printers typically utilized thermal paper imaging. More recently, laser and ink jet printing of incoming facsimile copies has become common. Also, many computer modems support the Group 3 digital standard and thus allow computers to operate both to send and to receive facsimile copies of documents.
Facsimile transmission of copies of documents works reasonably well. However, a number of problems have been identified. One problem that has been identified is that facsimile copies often do not provide the level of image resolution that some applications require. Another problem is that facsimile transmissions typically consume more transmission bandwidth than may be necessary. This is compounded by the problem that, in most cases, facsimile transmissions utilize an entire circuit-switched connection, as contrasted to sharing of circuits as is found in packet-switching solutions.
One solution to these problems that has been found arose naturally from the use in many instances of computers on both ends of facsimile transmissions. On the one end of a connection, a computer emulates a facsimile transmitter, and on the other end, another computer emulates a facsimile receiver. Standard computer scanners can be utilized to scan in documents. Similarly, standard computer printers can be utilized to print out received documents. In between, digital images of the documents are converted to the required Group 3 standard format before transmission and then converted from the Group 3 standard to a standard computer output format before being printed.
One solution is termed “Digital Sending”. Digital sending eliminates the conversions from and to the Group 3 standard. Instead, a document is scanned into a standard internal computer image format, such as Portable Document Format (PDF) from Adobe Systems Incorporated, Tagged Image File Format (TIFF), Joint Photographic Experts Group (JPEG) format, Bit-Map (BMP) format from Microsoft Corporation, etc. The document is then transmitted to a receiving system in the specified internal computer image format, where it can be manipulated, stored, or printed, as desired. While a transmission can be over a circuit-switched network, it is more frequently done over a packet-switched network, such as the Internet, or a corporate intranet. Typically, documents are transmitted as e-mail file attachments.
Originally, digital sending mirrored the typical e-mail environment. An e-mail message with one or more attached documents would be sent from one computer to another. However, as the cost of processing power continues to decline, it has become cost effective to utilize commodity processors in some auxiliary or peripheral devices such as printers and scanners. At the same time, these auxiliary devices are frequently being connected directly to networks instead of computers in order to more easily provide sharing of such among multiple computers and computer users. One result of this is that these auxiliary devices can now support functions such as e-mail that previously were limited to computers.
The incorporation of e-mail capabilities within auxiliary devices such as printers and scanners allows these devices to be utilized in digital sending. A scanner can be used to scan a document into a specified format and then to transmit that document as an e-mail attachment to a recipient. Similarly, a printer can receive an e-mail containing a document in a particular format and print it out. Especially useful for digital sending are all-in-one or multifunction devices that provide scanning and printing, and even facsimile transmissions. Some current examples of stand-alone devices capable of digital sending and/or receiving are the 9100C digital sending device and the LaserJet 8150 multifunction device from Hewlett-Packard Company of Palo Alto, Calif.
One problem that remains is that of delivering scanned documents to digital receiving devices that have either limited display area or limited bandwidth. Some examples of these are web-enabled cellular telephones, two-way pagers, and personal data assistants (PDAs). All of these devices have both problems. First, they have very limited display space. It is typically possible to only display a small portion of a scanned page at a time with these wireless, portable, web-enabled digital receiving devices.
Secondly, the wireless networks used to communicate with them typically have very limited bandwidth. One problem with wireless networks today is that scanned documents are typically relatively large. One reason for this is that computer readable image files typically require either bits or vectors to represent their contents. Transmitting a scanned document across a wireless network to a web-enabled digital receiving device can conceivably consume the entire wireless network bandwidth for a substantial period of time.
It would be advantageous to provide a mechanism for a wireless device with limited display area or limited bandwidth to be able to act effectively as a digital receiving device.